rhuMAb VEGF is an experimental humanized monoclonal antibody produced by Genentech using recombinant DNA technology. Antibodies are proteins that can protect the body from foreign invaders, such as bacteria and viruses. rhuMAb VEGF is a monoclonal antibody to vascular endothelial growth factor (VEGF), which is present in a wide variety of normal tissues but is produced in excess by most solid cancers (tumors)> In the setting of cancer, VEGF promotes the growth of blood vessels that bring nutrients to the tumor cells. In laboratory studies, rhuMAb VEGF inhibits the growth of many different cancers in animals by blocking the effects of VEGF.